Air filter



r In, Il, 'H Ill: llllli 2x 2 Sheets-Sheet l G. sLAYTER Er AL OriginalFiled Sept. 14, 1951 May 30, 1939.

May 30, 1939. G. sLAYTER ET AL Original Filed Sept. 14, 1951 2Sheets-Sheet 2 Patented May 30, 1939 e UNITED STATES PATENT yOFFICE AmFILTEa Games Slayter, Newark, and Jan Stuart Irvine, Toledo, Ohio,assignors, by mesne assignments, to Owens-Corning Fiberglas Corporation,a corporation of Delaware ApplieationSeptember 14, 1931, Serial No.562,752

`Renewed August 2,3, 1938 claims. (ci. iss-49) At the present timefilters of this type which ,l

are in commercial use ordinarily comprise a filter- 10i ing medium madeof some kind of metal treated with oil and enclosed in a metalcontainer. These filters are too expensive to be thrown awaywhen theybecome clogged with dirt, so that they must be renovated by av cleaningprocess. This requires additional equipment and involves labor Vandexpense, 'and' is objectionable for various other reasons. L

An object of the present invention is to provide a practical filterwhich can be made very cheaply so that when its efciency is impaired byl-the accumulation of dustand dirt it can be discarded and replaced by anew filter at little expense. I Other objects of the invention willappear hereinafter.

In the accompanying drawings: Fig. 1 is a front elevation of a filterconstructed in accordance with the principles of our invention.

' 30 Fig. 2 is a sectional elevation at the line II-II on Fig. 1.

Fig. 3 is a sectional detail of the cover or container, the sectionbeing taken at the line III-III 'on Fig, 1, with the ltering mediumomitted.

Fig'. 4 is a fragmentary detail view of a metal reenforcing strip;

Fig. 5 is a fragmentary elevation view showing a modified form of thecover.

Fig. 6 is a perspective viewl partly broken away,

of the cover or container shown in Fig. 1.

Fig. 7 is a section at theline VII-VII on Fig. 5 and shows a'modied formof the metal reenforcing strips.

Fig` 8 is a fragmentary view of the form of reenforcing strip shown inFig. 7.

Referring particularly to Figs. 1 and 2,r the filter comprises a pad orfiller I0 of filtering material, and a coveror container II. Thefiltering. material I0 is preferably made of fibrous glass,

commonly known as glass wool. Thisrmaterial is made by subjecting astream of molten glass to the action of air or steam under considerablepressure, thereby reducing the glass to threads or filaments whichaccumulate in a loose mass. This rglass While still at a hightemperature is treated with a heavy oil which adheres to the glass. Thistreatment serves to temper the glassv and give it a semi-dry coating ofviscous oil. Preferably, a heavy oil is used having a low cold test,which oil has been refined to .remove all odor and which contains about10% to 25% wax. The composition of such an oil and one method oftreating the glass fibers therewith are fully set forth in Patent No.2,068,202, January 19, 1937, to Donald C. Simpson, It is found thatglass wool treated 10 in this manner provides a filter which isefiicient through a wide range of temperatures, without any running ordripping of the oil. The oil will not run off at a temperature of F. andis sufficiently sticky or viscousto operate effectively 15 as a dustcatcher at temperatures of. 20 F. or more below zero.

The pad I0 of filtering, material may be made suiiiciently compact toretain its shape without external support, so that it can be usedwithout 20 the cover I I. 'Ifhe use of` a cover, however, hassubstantial advantages. n

'The cover or container II is. preferably made in whole or in part ofheavy paper, cardboard or fiber board. If desired, it may be treatedwith 26 some suitable oil-proofing material such as varnish, shellac orsilicate of sodato make it impervious to the action of the oil comprisedin the filtering medium. It is found in practice, however, that when thefilter is treated with an oil 30 of the character above indicated, whichdoesk, not run, it has comparatively little effect on the paper cover,so that an cil-proofing treatment is ordinarily unnecessary.

The container II comprises two sections, 35 namely, an inner section I2and an outer section I3, whichare substantially similar in constructionexcept that the inner section I2 is of slightly smaller dimensions so asto telescope within the section I3. The front and rear faces of the con-40 tainer consist of open-work comprising a `multiplicity of openings I4to permit the free passage of air through the filter. The structurecomprises parallel ribs or strips I5 extending horizontally across thefilter and vertical parallel in- 45 l tersecting strips I 6, thusproviding substantially rectangular openings Il. The cover sections I2and I3 are provided, respectively, with flanges I 1 and I8 extendingfsubstantially at right angles to the body of said sections. The flangesI8 5.0 forming the outer edge portion of the filter are outwardly bulgedor curved, as indicated in the drawings. In other words, the free edgesI9 of the flanges I8 are bowed outwardly and spaced from the flanges I1,except at the corners of the 55 container. The material of which thecontainer is made has a certain amount of resiliency, so that when thefilter is'slipped into position in a frame 2|! (Fig. 2) the resilientsides I8 are pressed inward towards the end flanges II and are held witha yielding pressure extending substantially throughout their length,against the retaining walls of the frame 2II, thus avoiding leakage ofair between the lter and said frame. This construction provides a simpleand practical means for obtaining a substantially air tight connectionbetween the filter and the frame 20 in which the filter is placed whenin use.

The end strips I8 may be secured together at the corners of thecontainer by metal corner pieces 2|. In assembling the parts, the filterpad is inserted within the inner cover piece I2. The outer cover sectionI3 is then placed over the section I2 and secured thereto as by means ofsmall brads or staples 22, thus holding the parts in assembled relation.If desired, the ends of the staples may be bent inward, as shown in Fig.'7, to clamp the parts in position.

Metal reenforcing strips 25 are attached to the inner faces of eitherone or both of the cover sections I2 and I3. These strips, as shown,extend transversely of the lter from one edge thereof to the other. Saidstrips are formed with tangs 26 at their ends and also at intermediatepoints by which the strips are secured in position. The longitudinaledges 21 of the strips are preferably bent or curved upwardly to stiiensaid strips, so that they serve to stiffen the front and rear walls ofthe container, thus providing a substantially rigid structure.

Prongs 28 provided at intervals along the reenfocing strips arepreferably formed by stamping them out of sheet metal comprising saidstrips and bending them upwardly at right angles. These prongs projectinto the filter pad and serve to quilt or hold the filtering material inposition, preventing sagging or matting of said material. As shown inFigs. 1 and 2, all of the reenforcing strips 25 with their prongs 28 areattached to the inner cover section I2, a reenforcing strip beingprovided for and attached to each of the transverse ribs I5. Obviouslythe number of strips used might be reduced and the arrangement otherwisemodified. A modification is shown, for example, in Fig. 7, in which thereenforcing strips are placed alternately on the .inner and outersections I2 and I3, so that both said sections are reenforced. Thisarrangement also provides prongs 28 extending alternately from oppositecover sections. Said prongs may be made of a length to extend partly orentirely through the filtering pad. The reenforcing strips shown inFigs. '7 and 8 are also of somewhat modified construction comprising aflat body portion and an edge flange 29 projecting at right anglesthereto.

Fig. 5 illustrates a modified arrangement of the openings I4, theopenings in each horizontal row being in staggered relation to those ofthe adjoining rows. This provides a somewhat stronger construction.Also, it permits the openings I4 in one cover section to be offset withrespect to those of the opposite cover section so that the air passingthrough the filter, instead ofe going in a straight line, is deflectedlaterally to a certain extent. In this manner air currents are broken upand the air is caused to move in a devious path through the lter,whereby the eiectiveness of the latter is increased.

Modifications other than those herein disclosed may be resorted towithin the spirit and scope of our invention.

What we claim is:

1. A container for an air filtering material. said container made offibrous material and comprising front and rear telescoping sections.each section including a substantially flat rectangular body portion,edge portions extending at right angles thereto, each said body portionconsisting of open-work providing openings for the passage of airtherethrough and through the lter, and metal reenforcing strips attachedto the inner face of one of said sections and extending transversely ofsaid section from one edge to the other thereof.

l2. A container for an air filtering material, said container made offibrous material and comprising front and rear telescoping sections,each section including a substantially flat rectangular body portion,edge portions extending at right angles thereto, each said body portionconsisting of open-work providing openings for the passage of airtherethrough and through the filter, and angular sheet metal reenforcingstrips secured to the inner face of one of said sections and extendingtransversely thereof.

3. A container for an air iiltering material, said container made offibrous material and comprising front and rear telescoping sections,each section including a substantially fiat rectangular body portion,edge portions extending at right angles thereto, each said body portionconsisting of open-work providing openings for the passage of airtherethrough and through the lter, and angular sheet metal reenforcingstrips secured to the inner face of one of said sections and extendingtransversely thereof, said strips being formed with integral prongsprojecting perpendicularly therefrom.

4. A nlter comprising a flat rectangular pad of fibrous filteringmaterial, a container for said pad comprising front and rear telescopingsections, at least one of said sections being made of fibrous material,the body portions of said sections having open formation providing amultiplicity of openings for the passage of air through the lter, andmetal reenforcing strips extending transversely ofthe filter andattached to the inner face of said section of fibrous material, saidstrips being formed at shortintervals with integral prongs extendingoutwardly therefrom and projecting into the ltering material.

5. A filter comprising a flat rectangular pad of fibrous filteringmaterial, a container for said pad comprising front and rear telescopingsections, at least one of said sections being made of fibrous material,the body portions of said sections having open formation providing amultiplicity of openings for the passage of air through the filter, andsheet metal reenforcing strips attached to the inner face of saidsection of fibrous material and extending transversely of said sectionin parallel relation, said strips being angular in cross-section andformed with integral prongs projecting therefrom into the filteringmaterial.

6. A filter comprising an elastic pad of fibrous filtering material anda paper container therefor, said container comprising front and reartelescoping sections, each section consisting of a fiat rectangular bodyand integral edge anges of resilient paper material, the flanges of onesection overlying those of the other, said overlying ange portions beingbowed outwardly and adapted, when the lter is inserted in a frame,

to be sprung inwardly by the walls of said frame and provide asubstantially air tight seal between said frame and the walls of thefilter.

'1. A filter comprising a rectangular ilat body of brous filteringmaterial, metal reenforcing strips extending transversely of said body,and prongs projecting from said strips into said body.

8. A lter comprising a rectangular fiat body of brous iilteringmaterial, metal reenforcing strips angular in cross-section extendingtransversely of the nlter in parallel relation at uniformly spacedintervals, and prongs formed integrally with said strips and projectingperpendicularly therefrom into the ltering material at spaced intervalsalong the strips.

9. A filter unit comprising, in combination, a mtering medium, acontainer therefor including a rectangular body and iiange portions ofresilient material forming the edges of the container, said flangeportions being bowed outwardly and yieldingly movable inwardly bypressure applied along their outer surfaces whereby the iilter unitlmaybe inserted in a supporting frame having an opening of a size and shape.to receive and t said unit with said flange portions pressed inwardlyand resiliently held in sealing contact with the walls of said opening.

10. A filter unit comprising a filtering medium, a container thereforincluding a body and iiange portions of resilient materialformng theedges of said container, said unit being adapted to occupy an openingdeiined by frame members and to have its ange portions forced inwardlytoward the body of the lter and thereby hold the filter in position andprovide a substantially air tight seal when said unit is inserted in theopening dened by the frame members.

GAIVIES SLAYTER. JAN STUART IRVINE.

